The present invention relates to a method and apparatus for making X-ray images. More particularly, the invention relates to improvements in a method and apparatus for making X-ray images without the use of conventional X-ray film. Still more particularly, the invention relates to a method and apparatus for making X-ray images on sheet-like dielectric receptors which are exposed to X-rays in the interelectrode gap of an ionography imaging chamber and are thereupon developed by resorting to xerographic techniques. The invention also relates to novel and improved means for supporting and advancing sheet-like receptors in the course of exposure to X-rays and during further processing.
It is known to produce latent images of objects on a sheetlike dielectric receptor while the receptor is located in the interelectrode gap of an ionography imaging chamber. The gap is filled with a compressed gaseous medium, preferably a noble gas, which is an efficient absorber of object-modulated X-rays and creates secondary electrons with the result that the receptor is provided with an electrostatic latent image which is thereupon made visible in a developing apparatus by using electrostatically attractible toner material. In the last stage, the toner image is fixed on the receptor in a manner known from the art of xerographic copying or printing.
A drawback of presently known methods and apparatus of the just outlined character is that the making of a fixed toner image takes up too much time. Dielectric receptors are introduced into and removed from the imaging chamber by hand. Also the transfer of receptors, which carry latent images, to and from further processing (developing and fixing) stations is effected by hand. Automatic transport of such receptors was considered impractical or impossible because an X-ray image is normally without margins (i.e., the image covers the entire exposed side of the receptor) so that the transporting means would have to engage those areas of a receptor which are contacted by toner material. The provision of an unexposed margin on receptors (which margin could be engaged and moved by an automatic transporting mechanism) is undesirable because the margin would have to be removed upon completion of treatment and the removed material would represent a highly expensive waste which would have to be processed (disposed of) in a costly and time-consuming manner. Moreover, the provision of margins would complicate the making of X-ray images on sheets with rounded corners which are preferred by technicians and physicians due to convenience of manipulation and storage.